Peer feedback is an effective instructional strategy for improving students' argumentative essay writing in higher education. However, little is known how do differently or similarly bachelor's and master's students perform in their peer feedback activities for essay writing. This study sought to identify the role of education level in students' peer feedback performance for argumentative essay writing. In this exploratory study, 47 bachelor's students and 56 master's students from Wageningen University and Research participated and it took place in an online learning platform called Brightspace. In this platform, students first were asked to write an argumentative essay on the provided topics, and then they were asked to give feedback to their peers' argumentative essays based on the given criteria. The results showed that there is a difference between bachelor's and master's students' peer feedback performance. Master's students provided more cognitive feedback than bachelor's students. That means master's students identified problems in their peers' argumentative essay writing more than bachelor's students and they also provided more justifications in their peer feedback. Based on the results, recommendations for future practice are presented. [For the complete volume, "Proceedings of International Conference on Studies in Education and Social Sciences (Antalya, Turkey, November 11-14, 2021). Volume 1," see ED625228.]